1. Field of the Invention
This invention relates to a process using mixed basic metal oxide catalysts for production of unsaturated aliphatic and alicyclic chains by dehydrogenation of aliphatic and alicyclic hydrocarbon compounds and aliphatic and alicyclic substituted aromatic hydrocarbon compounds. One important dehydrogenation is the reaction of ethylbenzene in the presence of a mixed basic metal oxide catalyst according to this invention to produce styrene.
2. Description of the Prior Art
Borates and boron compounds have been used in partial oxidation of hydrocarbons, such as boric acid to oxidize long chain normal paraffins in the liquid phase (Illingworth, G.F. and G.W. Lester, ACS Petroleum Division Preprints, 12, No. 3, 161 (1967)) and oxidation of n-dodecane in the liquid phase to the corresponding alcohol (Lee, K.W., M.J. Choi, S.B. Kim and C.S. Choi, Ind. Eng. Chem. Res. 26, 1951 (1987)). Boric acid has been used by coating reactor walls in the combustion of methane to eliminate free radical destruction at temperatures of less than 5l3.degree. C. (Kegeyan, E.M., I.S. Vardanyan and A.B. Nalbandyan, Kinetics and Catalysis 17, No. 4,749-754 and No. 4,755-759 (1976))
A number of publications describe oxidative methylation of toluene performed in Russia: Chemical Abstracts 97:127153 K (1982) teaches non-catalytic methylation of toluene depended mostly on pressure and PhMe/O/CH.sub.4 molar ratio; Chemical Abstracts 99:70137t (1983) teaches oxidative methylation of toluene using a Ni--V oxide or V oxide catalyst; Chemical Abstracts 101:74734t (1984) teaches oxidative methylation of toluene in presence of 0 (max. 15 percent in reaction mixture) results in products including styrene; Chemical Abstracts 101:38205 n (1984) teaches simultaneous production of styrene, ethylbenzene, benzene, and phenols by reaction of toluene with C.sub.1-4 alkanes in the presence of O and Fe.sub.2 O.sub.3 or TiO.sub.2 at 600.degree. -800.degree. . Productivity increased at higher pressure in presence of H.sub.2 O.sub.2 and/or (Me.sub.3 C).sub.2 O.sub.2; and U.S. Pat. No. 3,830,853 teaches reaction of toluene with a lower paraffin hydrocarbon in the presence of oxygen at 600.degree. -900.degree. C. and space velocity of 2000- 10000 hour-.sup.-1.
Styrene is an important commercial unsaturated aromatic monomer used extensively in the manufacture of plastics by polymerization and copolymerization. On a commercial scale, the great majority of the world's styrene is produced by dehydrogenation of ethylbenzene A review of styrene synthesis processes is given in Kirk-Othmer, Encyclopedia of Chemical Technology, Third Edition, Vol. 21, Styrene, pgs. 770-801.One commercial process for production of styrene is the UOP Styro-Plus process using ethylbenzene and superheated steam under vacuum for the catalytic dehydrogenation of ethylbenzene as taught by Ward, D.J. et al, Hydrocarbon Processing, Vol. 66, No. 3, March 1987, pgs 47-48. Use of coke-covered alumina and boron/alumina catalysts for oxidative dehydrogenation of ethylbenzene is taught by Fiedorow, R., W. Przystajko, M. Sopa and I.G. Dalla Lana, The Nature and Catalytic Influence of Coke on Alumina: Oxidative Dehydrogenation of Ethylbenzene, Journal of Catalysis 68, pgs. 33-41 (1981). Oxidative dehydrogenation of ethylbenzene to styrene over metal pyrophosphates, such as cerium, tin, zirconium, and titanium phosphates and calcium magnesium, strontium, barium, nickel, aluminum, thorium, zinc and silicon phosphates is taught by Vrieland, G.E., Oxydehydration of Ethylbenzene to Styrene over Metal Phosphates, Journal of Catalysis 111, pgs. 1-13 (1988). This article teaches the condensed phosphate surface is the dominant factor as a catalyst and that the cation has little or no effect.